Female. This sex is unfurnished with horns. The elytra are the same colour as in the male, not spotted so much, if at all, and more rugose. Thorax black, with a few yellowish spots, formed like stars or rays on it. In other respects it resembles the male.
Drury adds to this insect the following remark—"I have observed many species of beetles whose males have been furnished with horns, either on the head or thorax, but in which the females have none, but have those parts quite smooth and plain; and my observations incline me strongly to think that this rule subsists in every one of them, through the whole class. The instances I could bring in support of this opinion are too many to be admitted in this place."
The circumstance observed upon in the preceding note is certainly very interesting in a physiological point of view. In quadrupeds we find both sexes of cornuted species armed with horns; but in insects almost universally the males alone are provided with these appendages. It is also worthy of remark, that although in the majority of insects the females considerably surpass the males in size, yet in those species in which the males are cornuted, the females are almost invariably smaller than their partners.
Burmeister lays it down as a rule, that with regard to the differences of the sexes, their whole character may be thus distinguished; viz. that the male displays a preponderance of evolution, and the female a preponderance of involution; and observes, "that some beetles have processes upon the head and thorax, which, like the mandibles, can meet, like tongs, and thus serve as a weapon. This is asserted of Hercules and its large comrades." This opinion as to the uses of these horns can, however, scarcely be maintained, since the number of species in which the horns really meet is very few. Kirby and Spence observe, "What may be the use of these extraordinary appendages to the males, has not yet been ascertained. Whether the individuals of this sex are more exposed to the attack of birds and other enemies, in consequence of being more on the wing than the females, and are therefore thus provided with numerous projecting points of defence, is a question worth considering." It is also to be observed that these appendages, instead of being deciduous, as in many of the higher animals, are in insects component parts of the external skeleton.
There are a few exceptions to the observation of Drury; thus in the Lamellicorn genus Hoplites Dej. Catal. (Scarabæus Pan,) the females are cornuted as well as the males; and in the genus Osmia, belonging to the section of wild bees, Dasygastres, Latr., the females alone have the head furnished with two porrected horns.
BUPRESTIS (CHALCOPHORA) VIRGINIENSIS.
Plate [XXX]. fig. 3.
Order: Coleoptera. Section: Serricornes. Family: Buprestidæ.
Genus. Buprestis, Linn. Subgenus. Chalcophora, Solier.
Buprestis (Chalcophora) Virginiensis. Thorace lato fusco, punctis cupreis; elytris serratis atris, maculis cupreis, saturâque metallicâ. (Long. Corp. 1 unc. 1½ lin.)